During the coming year studies on ventricular performance and coronary circulation will be pursued in association with noninvasive radionuclide angiocardiography. This technique has established its viability and agreement with other more conventional techniques such as standard angiocardiography and determination of cardiac output by dilution curves. Moreover, the technique will be expanded to study coronary disorders, an increasing number of which are being diagnosed and managed. The primary usefulness of the technique is in the identification of patients with symptoms of coronary artery disease who acturally need coronary arteriography and cardiac catheterization. A number of patients are now being examined, both at rest and during exercise, to determine whether or not significant coronary arteriography and cardiac catheterization. A number of patients are now being examined, both at rest and during exercise, to determine whether or not significant coronary occlusive lesions are present. In the latter circumstance, nearly all patients with coronary artery disease requiring surgery demonstrate a decrease in the ejection fraction and in cardiac performance during the exercise portion of the radionuclide angiocardiogram.